Conventional disc planters typically have a frame attachable to a towing vehicle. The frame usually comprises a pair of parallel support arms spaced vertically, one above the other. The arms are hingedly attached to a support plate or beam which is attached to the towing vehicle. A support fame is attached to the other ends of the arms to support the seed planting apparatus. A pair of discs are mounted on the support frame in addition to two press wheels which are spaced from and located behind the two discs. The discs are mounted on an axle to which is attached a disc lever to alter the lateral spacing of the discs relative to one another on the axle. Each pair of discs are arranged to cut a single furrow or groove in the soil into which the seed is deposited. Typically, a plurality of disc planters of the type described above are attached in parallel to the towing vehicle, the disc planters being spaced laterally from one another, to enable a number of rows of seeds to be sown simultaneously.
In operation, the plurality of disc planters are attached to the towing vehicle and the lateral spacing of the discs on the axles on which they are mounted is adjusted to suit the type of seed to be planted. The discs rotate about the axles to cut grooves in the soil as the towing vehicle is driven over the ground on which the seed is to be sown. The soil cut by the discs is typically thrown out in a sideways direction by the discs as it is cut, there being no actual control over the amount or direction of soil thrown. The seeds are dropped into the grooves made by the discs via grain tubes, the outlets of which are typically located between the discs and the press wheels. Once the seed has been dropped into the grooves, the press wheels push the soil into the grooves to cover the seeds. In some conventional embodiments a further wheel or wheels are located between the discs and the press wheels to cover the sown seeds before the soil is compacted further by the press wheels.